"Entitlement is a big factor; the way that men act and the aspects of masculinity that say that anger is an acceptable emotional outlet and other emotions are not acceptable," Tweten said.

"Either way, if you ignore them or if you respond, they lash out."

Alexandra Tweten. Image Supplied.

Among the ugliest ways some men respond when they're rebuffed is by criticising women's appearances.

"I think the most common insults are calling a woman ugly or fat, and they can definitely be brutal sometimes. A lot of times they’ll attack your biggest insecurity. It can be really scary and hurtful," Tweten said.

While she believes this problematic behaviour has always been a part of online dating, Tweten claimed a lot of it stems from the early 2000s and its pick-up artist culture.

"Before online dating, pick up artists were a big thing, telling guys how to manipulate women. They try to insult you so you’ll seek their approval and play these mind games to try to persuade women into sleeping with them," Tweten said.

"I definitely think you can still see some examples of that online."

Alexandra Tweten's book 'Bye Felipe' is out now. Image Supplied.

Over the years, she has become an expert of sorts on the verbal warfare leveraged by men, calling out sexist crimes committed online in her book Bye Felipe: Disses, Dick Pics, and Other Delights of Modern Dating.

"There's Boring Bob, who’s very unimaginative and calls you fat. There’s Nice Guy Nick, they guy that thinks that they deserve a girlfriend because they’re nice," she detailed.

"Michael Mansplainer, the guy that explains your profession to you. Filthy Frank, the guy that messages you disgusting, explicit messages."